Bernie Sanders prepares for showdown in Hillary Clinton's home state

Bernie Sanders is preparing for a showdown with Hillary Clinton in the crucial state of New York, after a hat-trick of primary wins that have re-energised his presidential campaign.

Mr Sander’s routs in Alaska, Washington State and Hawaii have dented Mrs Clinton's armour, leaving her exposed to losses as the contest moves to the country's more liberal northwestern states.

"Now that we're heading into a progressive part of the country, we expect to do much better," the socialist Vermont senator said after his victories at the weekend. "There is a path to victory."

Mrs Clinton has been eager to pivot her focus to the general election, aiming her attacks at Donald Trump, the Republican frontrunner in an implicit signal she believes the Democratic nomination is already hers.

But Mr Sanders' sweeping primary victories have given his underdog campaign a momentum she can no longer ignore.

Energising the electorate enough to prompt voter turnouts even bigger than those inspired by Barack Obama in 2008, Mr Sanders beat Mrs Clinton with more than 70 percent of the vote in all three states.

Most importantly, he won every district in Washington, the largest primary, meaning he will likely take the lions share of its 101 pledged delegates, and so significantly narrow Mrs Clinton's lead of approximately 300.

The former secretary of state is additionally bolstered by the support of the majority of super delegates - the 712 party officials and establishment figures whose votes are able to significantly influence the election outcome.

But if Mr Sanders were to keep winning so much of the popular vote, the super delegates would come under intense pressure to switch sides.

Whilst Mrs Clinton performs well with Hispanic and African American voters, and so chalked up victories in the southern states, Mr Sanders has outperformed her with young people and white voters; a fact that should play to his advantage as the contest moves to the country's, majority white, northeast.

Students and supporters of Democratic presidential candidate Sen. Bernie Sanders during a campaign rally at Colorado State University in Fort Collins, ColoradoCredit:
AP

Polls now show the two democratic rivals in a tight battle for Wisconsin, which will vote this week.

A large enough win there will, Mr Sanders' campaign hopes, slingshot him into New York. The state where Mrs Clinton was a senator and that provides the highest number of delegates left to win apart from California, is a battle she neither can afford to lose.

Mrs Sanders' campaign has been laying the groundwork for all out war, intending to barnstorm the state as if he were running for governor.

In an aggressive tactic, they are also commissioning polls to show which contrasts between he and Mrs Clinton, be it their positions on Wall Street, healthcare or the environment - could do her the most damage in this home state.

Mr Sanders' campaign is lobbying the Democratic National Committee to organise a debate in the week before the primary.

“We don’t mind being the away team in the Hillary home game in New York,” Tad Davine, Mr Sanders' senior strategist told the Washington Post.

Mr Sanders has drawn strong support from voters with a populist message that rails against police brutality, a too-low minimum wage, soaring student debt and other societal ills.

In particular, millennials and first-time voters have been drawn in by his concerns about economic equality and call to reduce the influence of billionaires on the campaign finance system.

Democratic presidential candidate Hillary Clinton speaks during a rally at Rainier Beach High School in Seattle, Washington. Credit:
Getty

Stepping up his attacks against Mrs Clinton yesterday, Mr Sanders was openly sarcastic about her reliance on big money donors in the presidential campaign.

He called it “obscene” that Mrs Clinton “keeps going to big money people to fund her campaign,” citing some 50 million dollars in contributions from Wall Street donors.

He mentioned a fundraising dinner being hosted next month by actor George Clooney, where supporters will have to donate at least $33,400 to attend, or $353,400, nearly seven times the annual median income, if they want "premium" seating.

"It is obscene that Secretary Clinton keeps going to big money people to fund her campaign," Sanders told CNN. "Our events, we charge $15 or $50 for people to come. So, it's not a criticism of Clooney. It's a criticism of a corrupt finance system."

By contrast Mr Sanders has set a historical record in campaign financing, repeatedly beating Mrs Clinton's fundraising totals by receiving an astronomical number of small popular donations.

“Ours is a campaign of the people by the people for the people,” Mr Sanders said. “Not just reaching out to billionaires across this country.”

The prospect of a Sanders nomination remains still very much a long shot.

But the recent victories have transformed the New York primary later this month, into a competitive race for the first time since the 1980s.

“Everybody thinks it’ll be big,” said Hank Sheinkopf, a New York-based strategist and former Clinton adviser. “If the turnout by African Americans is large, Secretary Clinton will win well. If the turnout is not large, she will not win.”

In so doing Mr Sanders has proven that Mrs Clinton cannot yet assume she will be the Democratic nominee.